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Comparison of PCR and clinical laboratory tests for diagnosing H. pylori infection in pediatric patients.

Vinette KM, Gibney KM, Proujansky R, Fawcett PT - BMC Microbiol. (2004)

Bottom Line: Especially in children, these tests may result in a false negative outcome because of patchy distribution of the organism in the stomach mucosa.Of the seropositive patients, 26 were ELISA positive, 13 were positive by Western blot, and 11 by both serologic methods.In addition, we found the current commercially available approved ELISA method appears unable to accurately detect H. pylori in this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Immunology Laboratory, Department of Research, Alfred I, duPont Hospital for Children, Wilmington, Delaware, USA.kvinette@nemours.org

ABSTRACT

Background: Histology and/or culture are generally considered the gold standard for the detection of H. pylori infection. Especially in children, these tests may result in a false negative outcome because of patchy distribution of the organism in the stomach mucosa. We have developed a PCR assay utilizing nested primer pairs directed against a subunit of the H. pylori urease gene (ureA). As part of a prospective evaluation of diagnostic tests to aid in detecting H. pylori infection in children, the aim of this study was to compare our PCR and Western blot assays with results obtained from histologic examination of biopsy specimens, rapid urease tests, and an FDA approved serologic assay and published PCR results to determine if we could validate the assays for diagnostic use on our patient population.

Results: Gastric biopsy specimens obtained from 101 pediatric patients were evaluated for the presence of H. pylori using histologic techniques, rapid urease (CLOtest) test and the PCR assay. Serum samples from each patient were assayed using both ELISA and Western Blot for antibodies to H. pylori. A total of 32 patients tested were positive by at least one of the methods evaluated. Thirteen patients had positive histology, 13 had a positive CLOtest, and 17 patients had positive H. pylori PCR. Out of the 13 CLO positive patients, 12 were positive by histologic analysis and all 13 were positive by PCR. Results of serologic tests on the same population did not correlate well with other assays. Twenty-eight patients showed serologic evidence of H. pylori infection, of which 9 were both CLO and histology positive and 12 were positive by PCR. Of the seropositive patients, 26 were ELISA positive, 13 were positive by Western blot, and 11 by both serologic methods.

Conclusions: The results obtained suggest that our nested PCR assay has the specificity and sensitivity necessary for clinical application when compared to standard histologic examination and rapid urease test. In addition, we found the current commercially available approved ELISA method appears unable to accurately detect H. pylori in this population. The Western blot assay yielded better concordance with CLOtest and histology, but not as good as the nested PCR assay.

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Sensitivity and specificity of the test methods evaluated for detection of H. pylori infection. The sensitivity and specificity of each test method was compared to our accepted biopsy gold standard – patients were considered to be infected with H. pylori if both rapid urease and histology tests were positive.
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Figure 2: Sensitivity and specificity of the test methods evaluated for detection of H. pylori infection. The sensitivity and specificity of each test method was compared to our accepted biopsy gold standard – patients were considered to be infected with H. pylori if both rapid urease and histology tests were positive.

Mentions: As culture of H. pylori from biopsy specimens was not performed in our study, other methods based on endoscopic examination (specifically CLOtest and histologic staining of the biopsy specimens) were considered the gold standard for determination of the sensitivity and specificity of the PCR and serologic assays. Based on the stated criteria, 12 of the patients examined as part of this study (11.9%) were diagnosed as H. pylori infected. Overall, the invasive methods were shown to be more sensitive and specific than the serologic methods used for this population. The data indicates identical sensitivity and comparable specificity of the nested PCR assay compared to the widely used gold standard methods (Figure 2).


Comparison of PCR and clinical laboratory tests for diagnosing H. pylori infection in pediatric patients.

Vinette KM, Gibney KM, Proujansky R, Fawcett PT - BMC Microbiol. (2004)

Sensitivity and specificity of the test methods evaluated for detection of H. pylori infection. The sensitivity and specificity of each test method was compared to our accepted biopsy gold standard – patients were considered to be infected with H. pylori if both rapid urease and histology tests were positive.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC338288&req=5

Figure 2: Sensitivity and specificity of the test methods evaluated for detection of H. pylori infection. The sensitivity and specificity of each test method was compared to our accepted biopsy gold standard – patients were considered to be infected with H. pylori if both rapid urease and histology tests were positive.
Mentions: As culture of H. pylori from biopsy specimens was not performed in our study, other methods based on endoscopic examination (specifically CLOtest and histologic staining of the biopsy specimens) were considered the gold standard for determination of the sensitivity and specificity of the PCR and serologic assays. Based on the stated criteria, 12 of the patients examined as part of this study (11.9%) were diagnosed as H. pylori infected. Overall, the invasive methods were shown to be more sensitive and specific than the serologic methods used for this population. The data indicates identical sensitivity and comparable specificity of the nested PCR assay compared to the widely used gold standard methods (Figure 2).

Bottom Line: Especially in children, these tests may result in a false negative outcome because of patchy distribution of the organism in the stomach mucosa.Of the seropositive patients, 26 were ELISA positive, 13 were positive by Western blot, and 11 by both serologic methods.In addition, we found the current commercially available approved ELISA method appears unable to accurately detect H. pylori in this population.

View Article: PubMed Central - HTML - PubMed

Affiliation: Immunology Laboratory, Department of Research, Alfred I, duPont Hospital for Children, Wilmington, Delaware, USA.kvinette@nemours.org

ABSTRACT

Background: Histology and/or culture are generally considered the gold standard for the detection of H. pylori infection. Especially in children, these tests may result in a false negative outcome because of patchy distribution of the organism in the stomach mucosa. We have developed a PCR assay utilizing nested primer pairs directed against a subunit of the H. pylori urease gene (ureA). As part of a prospective evaluation of diagnostic tests to aid in detecting H. pylori infection in children, the aim of this study was to compare our PCR and Western blot assays with results obtained from histologic examination of biopsy specimens, rapid urease tests, and an FDA approved serologic assay and published PCR results to determine if we could validate the assays for diagnostic use on our patient population.

Results: Gastric biopsy specimens obtained from 101 pediatric patients were evaluated for the presence of H. pylori using histologic techniques, rapid urease (CLOtest) test and the PCR assay. Serum samples from each patient were assayed using both ELISA and Western Blot for antibodies to H. pylori. A total of 32 patients tested were positive by at least one of the methods evaluated. Thirteen patients had positive histology, 13 had a positive CLOtest, and 17 patients had positive H. pylori PCR. Out of the 13 CLO positive patients, 12 were positive by histologic analysis and all 13 were positive by PCR. Results of serologic tests on the same population did not correlate well with other assays. Twenty-eight patients showed serologic evidence of H. pylori infection, of which 9 were both CLO and histology positive and 12 were positive by PCR. Of the seropositive patients, 26 were ELISA positive, 13 were positive by Western blot, and 11 by both serologic methods.

Conclusions: The results obtained suggest that our nested PCR assay has the specificity and sensitivity necessary for clinical application when compared to standard histologic examination and rapid urease test. In addition, we found the current commercially available approved ELISA method appears unable to accurately detect H. pylori in this population. The Western blot assay yielded better concordance with CLOtest and histology, but not as good as the nested PCR assay.

Show MeSH
Related in: MedlinePlus